| 1. What is the solubility product constant expression for MgF2? 2. What is the solubility product constant expression for Ag2CrO4? 3. The solubility of CaF2 (molar mass 78.1) at 18°C is reported to be 1.6 mg per 100 mL of water. Calculate the value of Ks under these conditions. 4. Estimate the solubility of La(IO3)3 and calculate the concentration of iodate in equilibrium with solid lanthanum iodate, for which Ks = 6.2 × 10–12. 5. Calculate the solubility of strontium sulfate (Ks = 2.8 × 10–7) in (a) pure water and (b) in a 0.10 mol L–1 solution of Na2SO4. 6. Cadmium is a highly toxic environmental pollutant that enters wastewaters associated with zinc smelting (Cd and Zn commonly occur together in ZnS ores) and in some electroplating processes. One way of controlling cadmium in effluent streams is to add sodium hydroxide, which precipitates insoluble Cd(OH)2 (Ks = 2.5E–14). If 1000 L of a certain wastewater contains Cd2+ at a concentration of 1.6E–5 M, what concentration of Cd2+ would remain after addition of 10 L of 4 M NaOH solution? 7.Calculate the [Ca2+] required to start the precipitation of calcium fluoride, CaF2, from a solution containing 0.0025 M F– at 25°C. Ksp for CaF2 = 3.9 x 10–11. (a) 6.4 x 10–7 M (b) 5.2 x 10–10 M (c) 4.8 x 10–3 M (d) 6.2 x 10–6 M (e) 1.6 x 10–8 M 8. The solubility products of AgCl and Ag2CrO4 are 1.8E–10 and 2.0E–12, respectively. Suppose that a dilute solution of AgNO3 is added dropwise to a solution containing 0.001M Cl– and 0.01M CrO42–.Which solid, AgCl or Ag2CrO4, will precipitate first? What fraction of the first anion will have been removed when the second just begins to precipitate? Neglect any volume changes. 9. Which of the following solubility product expressions is incorrect and why? (a) Cu2S, Ksp = [Cu+][S2–] (b) Co2S3, Ksp = [Co3+]2[S2–]3 (c) Ni(CN)2, Ksp = [Ni2+][CN–]2 (d) AuI, Ksp = [Au+][I–] (e) Cr(OH)3, Ksp = [Cr3+][OH–]3 10. The solubility of cerium periodate, Ce(IO4)4, is 0.015 g/mL of water at 25°C. Calculate its solubility product constant. Its formula weight is 904 g/mol. |
Subpages (1): Answers to Ch 19 EofCh Problems